1.“Our memories are always our own.”

Thinkstock

The truth is our memories are a social construction. Every time we share a memory with others, we edit it. For example, we often make our memories more appropriate or entertaining for the people we are talking to. This is why a good story generally gets better over time. On the flip side, every time we hear other people’s versions of events we have the potential to steal their memories – later telling their versions of accounts as our own, perhaps even coming to believe that these memories belong to our own lives. We are all memory thieves, and we often don’t even realise it.

2.“Someone who is not telling the truth is usually lying.”

Pixar

A person who says something that is demonstrably untrue is not necessarily lying – they could have what's known as a "false memory". A false memory is a recollection that feels like a memory, but is inaccurate in some way. We can have false memories of small details, such as getting people’s names wrong, or even of entire events that didn’t happen to us, or that didn’t happen at all – in my own research I go as far as convincing people they committed crimes that never happened.

3.“Long-term memory means things we remember for at least a few months.”

Sony

When scientists talk about "short-term" memory, they refer to the brain storing information for about 30 seconds. Anything over 30 seconds is generally referred to as a form of "long-term" memory. Long-term memory can last for a minute, or a lifetime.

4."I have memories from when I was a baby."

Pixar

Scientists generally argue that memories before the age of about two and a half are impossible. This is because our brains are not yet big and mature enough to meaningfully organise our world and record it for later. The term for this phenomenon is called "childhood amnesia". Scientists further argue that we have "partial childhood amnesia" between the ages of about three and seven, where our memories are still not as good or long-lasting as they will be over the age of about seven.

5."There's a thing called photographic memory."

Tsuyoshi_kaneko / Getty Images

You don’t have a "photographic" memory, and neither does any other adult. The closest thing to photographic memory is called "eidetic memory" – exceptional memory of scenes or pictures. Around 5% of children have been found to have eidetic memories, but rather than pointing to mental superpowers having an eidetic memory may actually be a sign of problems, as prevalence increases to 15% in children with developmental difficulties. Even if photographic memories can be said to exist, they are fallible and it appears that memory Photoshop exists right alongside it.

6."Everyone remembers exactly where they were when 9/11 happened."

BBC

Detailed and vivid recollections of where we were at the time of particularly significant historical events, such as the Paris bombings, 9/11, or the death of Princess Diana, are often inconsistent or incorrect. Despite this, our confidence in our memories of such events is often high; showing that confidence can be a poor indicator of accuracy.

7."Imagination and memory are two totally different things."

They're actually not. Our memories are incredibly complex, flexible, and creative. We use the same parts of the brain to picture things happening by engaging our imagination as we do when we remember things. Because the same brain cells can be used for imagination and remembering, these two processes can get mixed up. We can mistake things we just imagined with things we experienced. This is how memory scientists have been able to, through simple imagination exercises, convince people that they experienced emotional events that never happened, such as spilling the punch bowl at a wedding, being attacked by a dog, or going on a hot air balloon ride.

Our memories cannot be trusted, and imagination and memory can feel surprisingly similar.